/*
 * $AIST_Release: 0.9.0 $
 * Copyright 2011 Information Technology Research Institute, National
 * Institute of Advanced Industrial Science and Technology
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *    http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package util

import java.io.InputStream
import com.google.protobuf.CodedInputStream
import pbdata.Tables.KeyValue

/**
 * Table.KeyValue List(defined by ProtocolBuffers) Reader.
 */
class KeyValueList(in: InputStream) extends Iterator[KeyValue] {
  val cin = CodedInputStream.newInstance(in)
  var nextValue: KeyValue = null

  override def next(): KeyValue = try {
    if (!hasNext()) {
      throw new NoSuchElementException("EOF")
    }
    nextValue
  } finally {
    nextValue = null
  }

  override def hasNext(): Boolean = {
    if (nextValue != null) {
      return true;
    } else {
      val tag = cin.readTag()
      if (tag == 0) {
        return false
      }
      val builder = KeyValue.newBuilder()
      cin.readMessage(builder, null)
      cin.resetSizeCounter()

      nextValue = builder.build()

      return true
    }
  }
}
